查找素数

#include<iostream>
using namespace std;
int main() {
 int i, j;
 bool isprime;

 for (i = 1; i <= 100; i++) {
  isprime = true;
  //see if the number is evenly divisible
  for (j = 2; j <= i / 2; j++)
   //if it is,then it is not  prime
   if ((i%j) == 0)isprime = false;

  if (isprime)
   cout << i << "is prime.\n";
 }
 return 0;
}